[Coombs-negative autoimmune hemolytic anemia developed after formation of post-operative pseudoaneurysm for femoral neck fracture].

An 85-year-old woman was admitted to our hospital with severe anemia after nail-plate fixation of the left femoral neck fracture. The patient was diagnosed with Coombs-negative autoimmune hemolytic anemia based on the measurement of red blood cell (RBC)-bound IgG molecules per cell. Pseudoaneurysm of the left profunda femoris artery was detected on magnetic resonance imaging and successfully removed by surgical repair of the artery. Anemia promptly improved, and the number of RBC-bound IgG normalized after the surgery. The destruction of RBCs was thought to have been responsible for temporary induction of anti-RBC autoimmune antibodies.